In accordance with a rapid spread of information relevant apparatuses and communication apparatuses such as a personal computer, a video camera and a portable telephone in recent years, the development of a battery to be utilized as a power source thereof has been emphasized. The development of a high-output and high-capacity battery for an electric automobile or a hybrid automobile has been advanced also in the automobile industry. A lithium battery has been presently noticed from the viewpoint of a high energy density among various kinds of batteries.
An electrolyte material having ion conductivity is ordinarily used for a battery typified by a lithium battery. Above all, a solid electrolyte material has the advantage that the simplification of a safety device is intended by reason of no fear of liquid spill as compared with a liquid electrolyte material (a liquid electrolyte). Also, a Ge-containing solid electrolyte material containing a Ge element is known as a solid electrolyte material. A material which performs comparatively high ion conductivity is known among Ge-containing solid electrolyte materials; however, a Ge-containing solid electrolyte material is so high in reduction potential as to have the property of being easily subjected to reductive decomposition (Non Patent Literature 1).
Also, for example, the problem that a solid electrolyte containing Ge may not be used in combination with an anode active material such as metal lithium (an anode active material with an electric potential of approximately 0.3 V or less on the basis of lithium) for the reason that an electric potential for causing a reduction reaction of Ge is approximately 0.3 V on the basis of lithium is described in Patent Literature 1. In order to solve this problem, a battery, in which a solid electrolyte not containing Ge is used for a second solid electrolyte contained in an anode and a fourth solid electrolyte contained in a separator contacting with the anode, is proposed in Patent Literature 1.